Casein glue



Patented Oct. -26, 19 26.

.UNITED STATES PATENT OFFICE.

WILLIAM F. SCHROEDER, OF MINNEAPOLIS, MINNESOTA.

GASEIN GLUE.

v No Drawing.

mental in gluesof the casein type, but'I have discoyered that magnesium carbonate, when used with casein and sodium fluoride, does not decrease the adhesive quality of the applied glue but rather increases the efficiency of the glue and greatly lengthens the time that the glue in liquid form will maintain its adhesive efficiency. I have obtained 'a wonderfully efficient casein glue by the fol- 20 lowing formula:

. Per cent.

Casein Lime r 10 'qodium fluoride 8 Sodium sulphite 3 Magnesium carbonate 2 I have also determined, by-experiments but by varying thepercentages of magnesium carbonate from one to ten per cent. by varying the sodium fluoride from five to twenty )PQI'. cent and by varying the sodium sulphite from two to eight per cent, The above percentages are given in respect to weight.

The above noted substances will be commingled in dry form and will usually be sold in dry form, but when it is to be used, it will be introduced into water to form an emulsion and it is then, of course, that the chemical reactions that develop the adhesive qualities of the composit on will take place. After these reactions have taken place, the emulsion is adapted to, be used as glue or as a coating or to be commingled with other substances such as paint or calcimine, which sition is to be used simply as a glue, no additionsto the formula given except water that improved glues can be made substan- Application filed July 26, 1922. Serial No. 577,752.

contain color pigments. When the compowill be required.

As asubstitute for sodium sulphite. I have found that I can use tri-sodium phosphate,

both of these substances being salts of soda.

'I have also found that I can reduce the amount of magnesium carbonate required by using at least 1n part calciumcarbonate, both of WhlCh substances are carbonates, but

by far the best results are given by the use of magnesium carbonate; The carbonates absorb the ammonia which is developed in the chemical reaction that takes place when the glue" has been made in liquid form or in an emulsion and is allowed to stand for a considerable time. The ammonia, if. allowed to remain in the emulsion formed by the composition and'water, will, in a shorttime, destroy the adhesive qualities of the caseinglue, and, hence, the elimination of ammonia is important. Another important result is found in the fact that the set glue does not, as is usual, become so hard as to damage saws, planes and the like, but has a tough character capable of being readily cut 75 by sharp tools.

qMagnesium carbonate retards the hydrolysis of the casein," when the casein is subjeeted to the action of an alkali. Magne- Intestirnony whereof I afiix my signature.

WILLIAM F. SCHROEDER. 

